/* ==========================================================================
   Design System - Vietnam Night 2026 UI Kit
   ========================================================================== */

/* --- Variables (Design Tokens) --- */
:root {
  /* Colors */
  --color-bg-primary: #0a0604; /* Deep dark brown/black */
  --color-bg-secondary: #1a110d; /* Slightly lighter for cards */
  --color-bg-glass: rgba(26, 17, 13, 0.6); /* Glassmorphism background */
  
  --color-text-primary: #f8f8f8;
  --color-text-secondary: #cccccc;
  
  --color-gold-light: #f9f1d8;
  --color-gold-main: #d4af37;
  --color-gold-dark: #aa7c11;
  --color-gold-glow: rgba(212, 175, 55, 0.4);
  
  --color-red-accent: #c8102e; /* Vietnam Red */
  
  /* Gradients */
  --gradient-gold: linear-gradient(135deg, var(--color-gold-light) 0%, var(--color-gold-main) 50%, var(--color-gold-dark) 100%);
  --gradient-gold-text: linear-gradient(to right, #f9f1d8, #d4af37, #f9f1d8);
  --gradient-dark-overlay: linear-gradient(to bottom, rgba(10, 6, 4, 0.3) 0%, rgba(10, 6, 4, 0.9) 100%);
  
  /* Typography */
  --font-heading: 'Playfair Display', serif;
  --font-body: 'Inter', sans-serif;
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 2rem;
  --spacing-lg: 4rem;
  --spacing-xl: 8rem;
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;
  
  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

/* --- Base Reset & Typography --- */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-body);
  background-color: var(--color-bg-primary);
  color: var(--color-text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-sm);
}

a {
  text-decoration: none;
  color: inherit;
}

/* --- UI Kit Components --- */

/* Text Utilities */
.text-gold {
  color: var(--color-gold-main);
}

.text-gradient-gold {
  background: var(--gradient-gold-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline-block;
}

.text-center {
  text-align: center;
}

.section-title {
  font-size: 2.5rem;
  text-align: center;
  margin-bottom: var(--spacing-lg);
  position: relative;
  display: inline-block;
  left: 50%;
  transform: translateX(-50%);
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 2px;
  background: var(--gradient-gold);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 12px 32px;
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-normal);
  text-align: center;
  border: none;
  outline: none;
}

.btn-primary {
  background: var(--gradient-gold);
  color: var(--color-bg-primary);
  box-shadow: 0 4px 15px var(--color-gold-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(212, 175, 55, 0.6);
  filter: brightness(1.1);
}

.btn-outline {
  background: transparent;
  color: var(--color-gold-main);
  border: 1px solid var(--color-gold-main);
}

.btn-outline:hover {
  background: rgba(212, 175, 55, 0.1);
  box-shadow: 0 0 15px var(--color-gold-glow);
}

/* Cards (Glassmorphism) */
.glass-card {
  background: var(--color-bg-glass);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid rgba(212, 175, 55, 0.2);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.glass-card:hover {
  transform: translateY(-5px);
  border-color: rgba(212, 175, 55, 0.5);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

/* Layout Utilities */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.section {
  padding: var(--spacing-xl) 0;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-md);
}

/* Inputs / Forms */
.form-group {
  margin-bottom: var(--spacing-sm);
}

.form-control {
  width: 100%;
  padding: 12px 16px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--color-text-primary);
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  transition: border-color var(--transition-fast);
}

.form-control:focus {
  outline: none;
  border-color: var(--color-gold-main);
  background: rgba(255, 255, 255, 0.1);
}

.form-control::placeholder {
  color: rgba(255, 255, 255, 0.3);
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-fade-in {
  animation: fadeIn 0.8s ease forwards;
}